Controllable pitch propeller



Nov. 22, 1949 M. M. sENsENlcH 2,488,687

CONTROLLABLE PITCH PROPELLER Filed Feb. 20, 1946 4 $hetsSheet 1 Nov. 22, 1949 M. M. SENSENICH 2,488,887

CONTROLLABLE PITCH PROPELLER Filed Feb. 20, l946 4 Sheets-Sheet 2 Nov. 22, 1949 'SENSEMCH 2,488,687

CONTROLLABLE PITCH PROPELLER Filed Feb. 20, 1946 v {Sheets-Sheet s wwifw Nov. 22, 1949 M. M. SENSENICH 2,488,687

CQNTROLLABLE PITCH PROPELLER Filed Feb. 20, 1946 4 Sheets-Sheet 4 l atented Nov. 22, 1949 2,488,687 i ooNrRoLLAB'LE PITCHiPROPELIIER. I f "Martin M. Sensenich, Lancaster, Pa., assignor to Sensenich Corporation-g Lancaster, Pa., a corporation of Pennsylvania j A pplication February 20, 1946 SerialNo.648,945

This invention relates to controllable pitch propellers and has primarily in mind the socalled hydraulic control type.

The primary objects of this invention :are': to

provide means for increasin stepping up or multiplying the power of the thrust received from a movable member, such as a cross-head or spider, to the point where it is delivered to the blades to force them through opposed partially rotary movements to change their pitch, said cross-head or spider being'moved by any suitable means, such as fluid under the pressure of an engine low pressure lubrication system; and, to

provide reversely operating levers :disposed in the propeller hub outside f-a 'slidingsleeve reciprocated in said hub un der'the control'of suitable actuating means-and'the thrust of the propeller blades, and functioning ferredzto.

In practice it is round that the lubricating oil pressure employed in aircraft engines varies Widely according to the make of the engine, in some the pressure running to eighty (80) pounds as the means above re-' 2Claims. (c1. 170-16032) and over and in others being as low as around thirty or thirty-five pounds or less. Where the pressure'runs :to 80 pounds or even considerably less thereis no need to step it up by levers or other interposed means serving-the function mentioned in the preceding-paragraph, but

where the pressure is as low as around 35 to 40 pounds it is not sufficient to rotate the blades about their axes to the required pitch positions 7 and with the necessary certainty and speed in opposition to the centrifugal, aerodynamic and-j other forces to which said blades are subject, and this invention finds its primary field of use in controllable pitch propellers driven by engines employing a low pressure lubricating 011 system with oil pressure around 35 pounds, that my present invention for stepping up such pressure as it is eventually applied to the blades to change their pitch has a substantial'fieldof-application as of the present time. v I v In the accompanying drawings:

Figure 1 represents a View partly in side cleva- Of Fig. 5;

tion andpa'rtly in section of the hub androot portions of theblades'o'f a dual blade propeller embodying my invention and as secured to the s nesharts; 7

Figure'2, a view partly in front elevationkand partly in section thereof Figure 3, a sectional view on the line 3am Fig. 2,'lookin-g inthe direction of the arrows;

Figure 4, a section in theplane of line l--l Fig-ure 5, an inner side elevation 'ofone of the levers 40 as engaged by one of the'Ipins or finger-s 22 of the spider, 'c'ross-hea'dlor traveler 2l'an'cl engaging the compensating guide block 26 "re- 15' ceiving in its bore the corresponding pitch 2111-" justing stud or lug 25 of one of the blades 1;

Figure 6, an end plan viewof one of the levers I Figure 7, an edge elevation thereof;

Figure 8, an outer side elevation thereof; I Figure 9, aside elevation of the spider or trav-l eler 2| sating blocks 26'; and

Figure 11, anedge elevation thereof.

Figure 10, a plan View of one or the oompen- The drawings illustrate a twoblade 'or dual blade embodiment of =my'invention in a so-called hydraulic control type of controllable pitch projpellers, though of j course this invention is not restricted to a dual blade propeller, nor, considered in its broader aspects, is it necessarily limited to use with propellers of the so-called hydraulic control type. f

A propeller assemblyin' which the present in vention is embodied and employing fluid un der pres-sure as'its'c'ontrol actuating medium may be" said-"to be 'lcomprisedof four main groups of elements as follows the hub per se; the blades 1 with their rootsfferrules; end caps, split lock rings, bearingsra'ces', retaining collars or nuts, locking means for the latter, all in general or.

prior known construction and "design, their pitch bosses orpins and their weights where the latter are employed; the hydraulic or fluid pressure control mechanismy'and the power boosting. means interposedbetween the spider or crosshead 2| and the pitc h bosses or pins 25 or the blades. I

Referring now in detail to the drawings, S designates the engine shaft having a flange F to which is bolted the flange 4 or the propeller hub by means of bolts and nuts I 4 and'which. is provided with a boss B fitting in ,the large diameter rearportion of the rear centering support, guide-bush or bearing 3. 'I'he'shaft 5 1S 3 w hollow or formed with an oil or hydraulic fluid ward end, and is formed with three external duct or bore 0, there being provided any usual cylindrical portions, being an extreme rear end conventional means, not shown, for supplying reduced diameter bearing portion l6 making a oil or hydraulic fluid from the usual engine lubrisnug sliding fit in the reduced diameter from cation system and at the pressure of said system portion of the rear bush or bearing 3 for recipthrough the bore 0 of said shaft S to the hyrocatory movement therein; an intermediate exdraulic system and for shutting ofi said supply ternally screw-threaded portion [1, and a large at will, and there also being provided :1151131 condiameterbearing ,portion.l8,..making. a snug slidventional means, not shown, for: draining oil :1 ing .fit in the front bush or bearingz, 2 for recipirom said hydraulic system through said bore 0 rocatory movement therein, and is formed in of said shaft S into the crank case of the engine said front portion with a plurality of preferably when the supply of fluid under pressure through equi-distantly spaced locking slots I9 preferably the shaft S has been cut ofi, the-arrangement arranged-in a circular series and preferably exbeing such that when the supply duct is open. tending ventirely through the wall of sleeve 20.

the drain duct will be closed'andgwhen the drain- Thetthreadsiofi-the externally screw-threaded duct is open the supply duct will be closed, all in portion llxengagethe internally screw-threaded accordance with well known and usual practice traveler, spider or, cross-head 2| and the interin the art. nally screw-threadedadjusting nut 21.

The hub body I is formed with a central bores; V By holding the adjusting nut 21 against turnor opening extending at lright angles to the axis ing and turning the sleeve-20 in the spider or cross of said body and .a centering support or. guide headJl mar-idem; adjusting.,nut..21, saidspideril bush or'bearingi2'istbrazed,welded 'or .othe'rwis'e andnutilemay be ad iustedto .difierent positions, suitably "secured or formedfin' the front wallioff axially of the sleeve ZlLonbyreleasing the nut'2'l'f said opening "in axial alignment witha similar totturnlwithrsleeve in and .turningthesleeve 20 bush orbearing 3 similarly securedor iormedin 1 in.-spider. 2|l.the positiomof the latter, maybe. therear wall of 'saidopening and said bushesiorn adjustediaxiallyoftheqsleeve 20 and .also ,with bearings 2 and 3 maybe provided with suitable relation ton nut 2fl,vor,iby holding sleeve 20 against. bearing linings; as illustrated in any, suitable) rotation and. turning the nut ,2 l. thereon the latter mannenjand thepropell'ertmounti'ng flange A is may be. adius tedlaxiallyof the; sleeve 20 with: secured to the rear 'end'of the bush or hearing 3 ,,relation -t 0;.spide12 2Landrtherabutment .face2'l".

and,to the adjacent portions of the body I atlall A- removable .lockingstud; or pin-l5 screwed into it points aboutth'ebush or bearing 3 by weldingor. asuitable.screw=threaded.hole-in the wall of bush. bnazinglor injany other suitable-known manner.-. or bearing 2 and, having;.a.;preferably smooth tip.

Thenrear centering support or,guide-bush orv tosfitdm any,onelofsaidsslots l9'servesto .lock. bearing3 is preferably formedwitha radial inner said,sleeve 20against-anyiappreciable. rotary or.. rearwardly presented shoulder 5,"; that portion .of partially rotary qmovementa, bush ;3 in front of said shoulder 5 being of smaller Access tothe ,inlterior- OL-the hub may be had diameter than that to the rear-of 'saidshoulder .5 byfla suitable tool introduced through a screwand snugly receiving,.supportin andguiding .the threaded hole normally closed by a p1ug 29 ,fon: reducedirearlendiportionl6 ofth'e sleeve 20,1the 4oemanipulatingg,=the1+adiustingenut 21.7 as. above larger; diameter portionbf said; bush13 to'..the mentioned rear of the shoulder 5 receiving and holding in, The,traveler;-:-spidenor,crossrhead2llislformed-, proper centered. position the engine shaft, .boss withlalpairl of diametrically opposite arms, fingers, B andan abutment plate or, disc 33, ,bearing. or.pinsn22,extendingrlaterally-.-outwardly ofthe, against the shoulder 5andheld;in..place,by,the 45.:hubul in opposite directionsand these fingers, or 1 pressure ,ofboss B, a suitablefluid sealing; gasket pins,,22.engage,with.other parts of-theassemblagar 3510f any suitable preferably,compressible ma=-..- and preventithe rotation ofltheTspider-or cross- Y terialfbeing interposed. between the annularendr head-,2 lswith-l-thesleeve .Zltin t -as embl d e a-lface; of ,boss Bend .the radiallyrouter portion of, tion-;of:.thesparts.-=.- thelppposed rearlface of disc 33: 0 A thnustxorupiston rrode3lle having -a rearrende A,pitch,or adjustinglug orstud 25;.istsecured. nipplei-snugly slidably removably;;fitting;;in-;andtcj thel root end. ,ofleach. blade! I to extend. in: preferably throu h, thee-central; opening. of the f wardly" of the hub axially of the -.blade.at,a point.- abutment. plate r0122 disc Sit-extends len hwis remote,from the axis of the-blade... through-thersleever 2lliand= nearly to the cylinder-- Weights,v ll may bessecured v,toctherespective. v head:-or-,-front omcovenlplateuiili and haS-an'eXe- 1. blades, 1 .in such. angular positions as -to,tend tom ternally screw-,threadedznipple'extendinggthrouglr t turn said 'bladesto, and maintain ,themrtheirh a dishectformlpistorwlxand a fiexiblediaphragm-m high pitchjposition iduringh-thelrotation of thea oflany suitable: materialwsuchl-focrinstance asb propeller, unlessanduntil .counteractedgby their molded-tneoprenew A nutr3fi turning onptheexpositive action of the hydraulic mechanismacting= sor-treme front end portion of said threaded-fronts, to forcibly turn the blades'l to, and hold them in,, end nippkeextending zforwardsrbey ndr.saidadiar theirLlowpitch positionswhile the-oil or otherr phragm138iserves to tightly;clamp saidspistonr.3M- fluidiis supplied, under pressure, or.maintained,, andridiaphragm 138ebetweenasaid-nut.BSHandQann under pressure to saidhydraulic mechanism..- To annular flange-son,shoulder;;321integral: WithqOhz this .end each;,weight I I islconnecteditoaa bandri idly S o the forward d p ti0n"0fnSaid-3( ilwhich encircles thestem orferrule of acorre -a thrust ompistonrod-.30: The rear-.end'portio'nrpf: sponding blade ,1 and is provided with; a-nut and-s the thrustnor piston-trod; 30-:is formed v.or provided bolt -l3or other suitable means for drawing said: with aaepreferablyaannulan :shoulder: or: flange;3l;

bandglzinto tight binding and. locking engage integral-with or;-rigidly; secured .toxsaid' rod .302: miantwithsaidstem orierruletox hold the said.;- which exertsazthrust-againstwtherabutmentplatea; weight I l in any selected position, of angular ,ad-.-,- orsdisc, 33.,-

justmentl thereon. against i movement, relative" 'I'he(outerFperipheraleportiorrof;thediaphragm1r thereto. is clamped with a fluid tightzseal"betweerrithear,

The sleeve 20 is preferably integrallwithrthea front edge of theecylinder ElbaudrzthewcYlihder enlarged cylindrical cup A or cylinders 31; at-itsr for,- a J head'oncover plateB-l 5 which iszpreferably formed with an internally screw-threaded rearwardly- Admission of oil or hydraulic fluid under pressure into this chamber 39 through the hollow shaft S and thrust or piston rod 3E]v will exert a thrust on the abutment plate 33 and the cylinder head or cover plate 31, causing the latter .to move forward together with the cylinder 3'! its sleeve 20 and the spider or cross-head 2| carried by said sleeve, and release. of such fluid from said chamber 39 will permit the cylinder 31, with its head 37', sleeve 20 and the cross-head or spider 2| carried by the latter to be moved rearward by the partial rotary movement of the blades 7 about their aXes when released from the influence of the hydraulic fluid.

All parts thus far described are shown and described in detail in the Sensenich and Uhrich patent application, Ser. No. 596,442, filed May 29, 1945 for Controllable pitch propellers and are not of my invention except in so far as they are modified and form part of the combination of my present invention, which starts with the disclosure of said Sensenich and Uhrich application as a foundation and constitutes an improvement thereon primarily to provide a simple controlled pitch propeller of the so-called hydraulic type particularly adapted for operation by the oil of the lubrication system of engines employing low pressures, such for instance as of around 30 to 40 pounds pressure, though of course the degree of pressur may vary, though the higher the degree of pressure the less the need for means for stepping up the power of the hydraulic fluid as eventually applied to change the pitch of the blades.

The power boosting means comprises levers 40 respectively to connect the traveler, spider or cross-head 2| to the roots of the respective blades l, translating the linear movement of the crosshead 2| into rotary movement as applied to said blades, and increasing the power of the thrust of the cross-head 2| as actually applied to the blades 1.

Said levers 40 are respectively disposed in the hub body exteriorly of and on opposite sides of the sleeve 2| and are respectively pivotally mounted on pivot pins 4| disposed on opposite sides axially of the body of the axis of sleeve 2|.

The pivot pins 4| are secured to or in the body of the hub in any suitable manner, as by being driven with a tight drive fit into suitable holes or bores made through the wall of said body to receive them and by being made of a very slightly larger diameter, say one ten-thousandth of an inch, than the internal diameter of the holes into which they respectively are to be pressed or driven.

A spacing and reinforcing washer 42 preferably also having an opening of the same diameter as the hole or bore in which its pin 4| is to be forced is applied to each pin 4| and in assembled relation is in engagement with the wall of the hub adjacent the pin as pressed or forced into place and said washer 42 is preferably brazed to the body I.

As thus mounted each lever 40 will have a long arm and a short arm, the long arm being preferably substantially twice .as long as the short I I arm, 7

The long arm of each lever 40 has its free end notched or bifurcated as at to receive the corresponding finger or pin 22 of the traveler,

spider or cross-head 2|, and the free end of the short arm of each lever 4|) is formed with a shallower but wider slot 43 to slidably receive an adjusting and wear compensatin thrust block 26 which has an off-center bore receiving'the pitch boss, lugor pin 25 of the immediatelyadjacent root of the adjacent blade I; I

Each of the four outer edge faces of each of the square thrust blocks 26 will preferably be convexly 'radiussed or rounded to properly cooperate with the walls of their corresponding slots 43 in the free ends of the short arms of the levers 40 as the same swing about the axes of their respective pivot pins 4|, and preferably will be insertible in their respective slots 43 in any one of four positions according as may benecessary to obtain the proper adjustment either in'the original assembly or to compensate for wear.

This thrust block 26 per se, and the pitch boss, lug or pin 25 per se, and the details for connecting said pitch boss or pin25 to its blade root were known prior to my present invention, being shown and described in the above referred to Sensenich and Uhrich patent application.

With the parts constructed, arranged and combined as above described, assuming the blades 1 are provided with the weights II and normally are in their high pitch positions, the

levers 40 being in their neutral positions perpendicular to the axisof sleeve 20, and that it is desired to shift the blades. 1 ,to their low pitch positions for taking off or climbing, admission of oil under pressure to the chamber '39 will force the cylinder head 31 with cylinder 31, sleeve 20 and traveler, spider or cross-head 2| forward and' through the engagement of the fingers or pins 22 withthe walls of slots 44 in the free ends of the long arms of the levers 40 will swing said levers 40 about the axes of their respective pivots 4| and bytheir double length substantially doubling the force of the thrust of the hydraulic fluid received by the spider or cross-head 2| as the same is applied to the pitch bosses or lugs 25 by the short arms of the respective levers 40.

When the take-off or climb has been completed and it is desired to permit the blades to assume their normal high pitch positions for straight away flying, the supply of fluid under pressure to chamber 39 is cut off and the drain therefrom to the engine crank case is opened and the blades 1 bein released from the hydraulic control means will be turned to high pitch positions by the centrifugal and other forces and influences, including the weights II to which they are subjected, and in so doing will swing the levers 40 back to their initial neutral positions and said levers will simultaneously force the sleeve 20 with its connected cylinder 31 and cylinder head or cover plate 31' in the reverse axial direction back to their initial positions, the reverse movement of the cylinder head or cover plate 31' as it progresses expelling the oil from the chamber 39 into the engine crank case.

Of course the embodiment of the invention illustrated, while presently preferred, is merely one of many possible embodiments, and that simply as applied to a dual or two blade hydraulic control type of propeller, the construction and arrangement of parts would be varied appropriately fii'siwii a s2 imits: applinatiomitoo aepmpell'eliihajvingt m'om'e axes=respeetively fixed-'Teltivfitsaid hufiand-1' than two blades or to a propeller employingtea resmetively having ldng amfiportiohs and shorb difi'erent'tpowen;S011rcef0ra-c0ntr0lling fnheapiteh arm por ti*ons;- th "respeobive' long arm por movementsrofetheblades; and:theidetails;of.'thetions of sa'id ilev'rs'firegpgctivly engaginghsaidfi pow r-P m iplyingzsorincrea in zeouple or" cone spiderw be thrust"; thereby-in bne=--axia1'-=dir'eonecting means interposed betweenethe-spiderm tipn amd to-exer-t a thrust in the ireveme direc=- cross-headcandithe bladesamayibeivaried intaar; tio'n iuponzisaid e andrlthe .respectivenshdph'i; reat-amanww y s v rious :forms:orleversxmaxu arms of said leversrespetivelsi engagirigtheue be'-used,morrleversras suclr may be z'enti'relyz deispective pitch pins 'of the -respectiveblades -to par tedzifromwit suflicingzsozlongias there-lsrpro-l lo ilthiust theminone directioniunder,thethrusfioffi vided:some-spowel ing ormultiplying: said spider and -to receive thrust fromFthem-inw' means capable of increasing the power-receiveds thereverse directzmngv bye-theaspider-onzcrossehead 2lgaszappl-ied toztli'e 2.T'-A controllable"pitch' propeller comprising a blades-1;! sufiiciently toffunction properly inishlft hubi'to'be secured td a -engine haft. and. to have= g i hipitch of ithesbladesfl andtholdingethemw z,kits interiorin communicatiomwith' omeans foras-long ,ras. requirectior desired in .thenewly sadej supplying fluid u de pressure s to and s: lustedzpitchzp y comp at e y 10Wipovvfifltfv for draining =-fluid therefr0m,= propeller blades' means-sh mounted in said *hubf pitch pins respectively ex Lolaiimz tending from saidblades,- a sleeve mounted for A ntrol ablei'pit p p p i reciprocation--in said hub, and laspider carried-* hub tube secured-moan engineshait and to.have:--: infixed position by said sleeve, in combination its-:inlieriorsinzn communicatlonswitlr meansafonc ith l v pivotally-mountedinsaid'hub radisupplyingrfluidunder pressurethereto andrmeansi; 1-1y; t, of-'said j 1 t Swing about:axes for dra nin fl i r r m propeller blades? respectively fixed relative to said hub and re-- mountedrin saidihub,z':pitch pins respec y speotively having long' arm --portions and short tendingdr misaidibladeseazsleeve mounted fm arm portions; the res pective long arm portions reciprecafiiomim said'fhub2and havin f an of-said levers respectively engaging said spider ternal'ly .screwethreadedzporbmn, hydraulic mech v to be thrust thereby in one axial direction and anlsmw-foraforcingls said sleeveeinuone direction to ert a thrustin-the reverse direction upon axially thereof againfltjhe reverse thIUSt Of S QIidQ said. pider and the respectivelshortarms of aidf blades,:releasablemeanSiomlocking said sleeve levers.yespective1y engaging theqespective t hagainst::rotaryemovement:relative to: SaidZ hUbE-I pins 'ofith'e. respectivepbladsuto.thrust Whilfl Pe ttin itssaxial' movementathereingeax onedirection underthetlirusfrof=saidspiderand" spidethay ngecrewe re d engagement-wifihfilhfl to receive a thrust-"from them in" the reverse screw-threaded: portionofq'said s1eeve,z:and:an-r ad- 35.,(zdirecti0n justableapitch: movement-limiting; nlltiihQVifi-Q: MARTIN 1 s screwethreads. engagement with i the =1: screw-J threadedabportioni 01?; said: sleeve. andu anormallyti REFERENCES CITED r relativelys fixed; pant a-carrieds byathe;.hub;- 891M140 0 patent.

spider andanut-being' adjustable :to-vdifiere'nfiposi-f UNITED STATES PATENTS tionsaaxiallymfizsaid;sleeve: eitherssimultaneously- Number i Y in" the same axial ;direction and to thes-same -de- 2,233 468 ma a] o P f gnee on separately andrelatlvelyto each otherrin 4 2343:415 Keller Man 7 .5

combinatiomwithdevers pivotally mounted infisaid ihub: radiallyputside pfz'said-rsleevato swing; about i 

